Spin Battery Could Revolutionize Energy

Imagine an iPod or laptop battery that could be recharged, without a cord, simply by holding it near a magnetic field.

University of Miami professor Stewart E. Barnes is a researcher in the field of electro-magnetics, also known as “spintronics.” [Photo: Kathryn Wanless]

Traditional batteries work by using a chemical reaction — between substances like lithium and carbon, for example —?to produce the electrical current needed to operate a device like a laptop computer or an iPod.

In the future, that electrochemical technology may be replaced by a new type of battery developed by University of Miami physics professor Stewart E. Barnes, a researcher in the emerging field of magnetoelectronics, or “spintronics.”

Barnes has shown the possibility of creating a “spin battery” that would receive a charge simply by being placed near a large magnetic field. The battery would then convert the magnetic energy into electricity to power the laptop or iPod with “no chemical reaction involved,” says Barnes.

The technology is a long way from commercialization or even prototype development. So far Barnes has created a spin battery only at the nano-level, using minuscule magnets to create a battery that’s only the diameter of a human hair. To power a device like a computer, a spin battery would have to be made much larger. In theory, it could be made large enough to power a car, but Barnes thinks spin technology is more suited for small electronic devices.

If they can be built to scale, spin batteries would enjoy a number of advantages over traditional electrochemical batteries. For one, since no chemicals are involved, a spin battery might be more environmentally friendly. There’s also the matter of convenience: Spin batteries would be recharged without cords, with the iPod’s owner simply placing the device into a magnetic field. So far, Barnes says, the research hasn’t indicated how long a sizable spin battery would have to be exposed to the magnetic field to charge it.

Barnes has been working closely with researchers at the University of Tokyo and Japan’s Tohoku University. Now he’s looking for research funding from the National Science Foundation, U.S. Department of Energy and other agencies. Barnes says one agency that has expressed interest is the Defense Advanced Research Projects Agency (DARPA), the primary research office of the Defense Department.

The technology might be of more immediate use in computers, using magnetic memory, or MRAM. The specific research, called spin torque transfer, produces memory that is faster, uses less power and doesn’t disintegrate over time. Barnes calls it “a very, very efficient memory cell.”